Conductivity (resistivity) measurements are reliable overall indicators of water purity, and the accuracy of such measurements has improved significantly over the past few years. Conductivity measurements are, for example, used for the detection of impurities in steam/water circuits at power plants. The cation conductivity (`CC`) of a solution refers to the conductivity of that solution after it has been treated, e.g. has passed through a strong acid cation exchange resin, so that its cations have been replaced or exchanged by hydrogen ions (H.sup.+). Cation conductivity is also known as the acid conductivity or KHI value. Since the hydrogen ion has the highest specific ionic conductance of all ionic species, cation conductivity values are capable of improving the sensitivity of measurements for the detection of impurities in water, such as in steam/water circuits. For this reason, cation conductivity values are an effective method for detecting condenser tube leaks in water cooled condenser systems at power plants. The cation conductivity of a solution also gives a good indication of the concentration of anions present in the solution.
A reliable method for the detection of water cation conductivity values already exists. The method involves passing a sample of the solution through a strong acid cation exchange resin column. Any cations present in the sample solution and emanating from dissolved salts are exchanged for hydrogen ions, thereby forming acids corresponding to the dissolved salts. In other words, cations present in the sample solution salt are taken up on the resin while hydrogen ions on the resin are released into the water to associate with the anions originally associated with the cations, thus forming acids corresponding to the dissolved salts. The sample is then passed through a conductivity detection--or measuring cell, which consists of electrodes of specific area and surface condition, spaced a defined distance apart by a controlled cross-section of the process sample. The acid is usually more conductive than the salt, thereby producing an exaggerated conductivity measurement. The disadvantage of this method, however, is that the cation exchange resin is rapidly exhausted, particularly in cases where the steam/water circuit from which the water sample is taken is operated in a high all volatile treatment (`AVT`) regime.